Phytohormone Responses and Cell Viability during Salinity Stress in Two Creeping Bentgrass Cultivars Differing in Salt Tolerance

Salinity stress is becoming more prevalent in turfgrass management with the increasing use of recycled water for irrigation. Creeping bentgrass (Agrostis stolonifera) is a cool-season turfgrass species that contains significant cultivar variation in salt stress tolerance, but the mechanism related to this cultivar variation is not well understood. Our objectives were to determine whether differential hormone content could play a role in cultivar variation of salt responses and to evaluate whether cell viability assays using dye techniques could differentiate salt stress damage levels in turfgrass species. Therefore, a growth chamber study with potted plants was conducted to evaluate salt ion concentrations, physiological responses, and hormone analysis [abscisic acid (ABA), indole-3-acetic acid (IAA), jasmonic acid (JA), salicylic acid (SA), zeatin riboside (ZR), and ethylene] at 4, 8, and 12 dS·m−1 in relatively salt-tolerant ‘Mariner’ compared with salt-sensitive ‘Penncross’ creeping bentgrass. A hydroponics-based growth chamber study was performed for evaluation of whether dead-cell stains coupled with image analysis could be a quick method for indicating cell viability variation between cultivars. Greater salt tolerance was evident in ‘Mariner’ at 12 dS·m−1, which showed significantly lower electrolyte leakage, higher leaf relative water content (RWC), osmotic potential, photochemical efficiency, and photochemical yield compared with ‘Penncross’. A higher K+ and lower Na+ content was maintained in leaves of ‘Mariner’ compared with ‘Penncross’ while roots of ‘Mariner’ maintained higher Ca2+ content under stressed and nonstressed conditions. Phytohormone levels showed a decline in salt-stressed roots compared with nonstressed plants but ‘Mariner’ roots were able to maintain levels higher than ‘Penncross’. ‘Mariner’ leaves showed an increased accumulation of ABA, JA, SA, and ZR while roots maintained higher IAA and SA compared with ‘Penncross’. The results suggest that ‘Mariner’ was able to mitigate salt stress by better ion regulation and differential regulation of hormones compared with ‘Penncross’. ‘Mariner’ leaves and roots showed significantly lower dead cells compared with ‘Penncross’ under salt stress. The results suggest that staining for cell viability could be a useful technique for studying turfgrass stress or other cellular responses.

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Silicon ameliorates the adverse effects of salt stress on sainfoin (Onobrychis viciaefolia) seedlings

Plant Soil and Environment ◽

10.17221/665/2017-pse ◽

2017 ◽

Vol 63 (No. 12) ◽

pp. 545-551 ◽

Cited By ~ 1

Author(s):

Wu Guo-Qiang ◽

Liu Hai-Long ◽

Feng Rui-Jun ◽

Wang Chun-Mei ◽

Du Yong-Yong

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Adverse Effects ◽

Plant Growth ◽

Membrane Permeability ◽

Chlorophyll Content ◽

Salinity Stress ◽

Soluble Sugars ◽

Organic Solutes ◽

Relative Membrane Permeability

The objective of this study was to investigate whether the application of silicon (Si) ameliorates the detrimental effects of salinity stress on sainfoin (Onobrychis viciaefolia). Three-week-old seedlings were exposed to 0 and 100 mmol/L NaCl with or without 1 mmol/L Si for 7 days. The results showed that salinity stress significantly reduced plant growth, shoot chlorophyll content and root K+ concentration, but increased shoot malondialdehyde (MDA) concentration, relative membrane permeability (RMP) and Na+ concentrations of shoot and root in sainfoin compared to the control (no added Si and NaCl). However, the addition of Si significantly enhanced growth, chlorophyll content of shoot, K+ and soluble sugars accumulation in root, while it reduced shoot MDA concentration, RMP and Na+ accumulation of shoot and root in plants under salt stress. It is clear that silicon ameliorates the adverse effects of salt stress on sainfoin by limiting Na+ uptake and enhancing selectivity for K+, and by adjusting the levels of organic solutes. The present study provides physiological insights into understanding the roles of silicon in salt tolerance in sainfoin.

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Low pH alleviated salinity stress of ginger seedlings by enhancing photosynthesis, fluorescence, and mineral element contents

PeerJ ◽

10.7717/peerj.10832 ◽

2021 ◽

Vol 9 ◽

pp. e10832

Author(s):

Fengman Yin ◽

Shanying Zhang ◽

Bili Cao ◽

Kun Xu

Keyword(s):

Salt Stress ◽

Chlorophyll Fluorescence ◽

Salt Tolerance ◽

Salinity Stress ◽

Low Ph ◽

Nutrient Acquisition ◽

Mineral Element ◽

Mineral Contents ◽

Photosynthesis Efficiency ◽

Element Contents

We investigated the effects of low pH on the photosynthesis, chlorophyll fluorescence, and mineral contents of the leaves of ginger plants under salt stress. This experiment involved four treatments: T1 (pH 6, 0 salinity), T2 (pH 4, 0 salinity), T3 (pH 6, 100 mmol L−1 salinity) and T4 (pH 4, 100 mmol L−1 salinity). This study showed that photosynthesis (Pn, Gs, WUE and Tr) and chlorophyll fluorescence (qP, Φ PSII, and Fv/Fm) significantly decreased under salt stress; however, all the parameters of the ginger plants under the low-pH treatment and salt stress recovered. Moreover, low pH reduced the content of Na and enhanced the contents of K, Mg, Fe and Zn in the leaves of ginger plants under salt stress. Taken together, these results suggest that low pH improves photosynthesis efficiency and nutrient acquisition and reduces the absorption of Na, which could enhance the salt tolerance of ginger.

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Sucrose and Starch Content of Plant Parts as a Possible Indicator for Salt Tolerance

Functional Plant Biology ◽

10.1071/pp9840491 ◽

1984 ◽

Vol 11 (6) ◽

pp. 491 ◽

Cited By ~ 5

Author(s):

G Rathert

Keyword(s):

Salt Tolerance ◽

Salinity Stress ◽

Starch Content ◽

Percentage Increase ◽

Sensitive Species ◽

Ion Regulation ◽

Plant Parts ◽

Selection For ◽

Initial Root ◽

Sucrose Level

The effects of NaCl on total root and leaf sucrose and on total foliar starch in crops of differing salt tolerance were investigated during the early stages of salinity stress. Leaf sucrose level increased most in bushbean (sensitive) but less in rice (moderately sensitive), whereas it decreased slightly in soybean (moderately tolerant) and more in cotton (tolerant). Initial root sucrose was lowest in bushbeans, but this sensitive species showed the biggest percentage increase after salination. Foliar starch increased in sensitive crops but decreased in tolerant crops. NaCl-induced carbohydrate change in roots and laminae was correlated with tolerance of the species independently of ion-regulation behaviour. Sucrose and starch contents may assist in the selection for salt tolerance within species.

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Screening of rice genotypes for salt tolerance by physiological and biochemical characters

Plant Science Today ◽

10.14719/pst.2021.8.3.1098 ◽

2021 ◽

Vol 8 (3) ◽

Author(s):

Uttam Bhowmik ◽

Mohammad Golam Kibria ◽

Mohammad Saidur Rhaman ◽

Yoshiyuki Murata ◽

Md. Anamul Hoque

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Salinity Stress ◽

Crop Production ◽

Proline Content ◽

High Yield ◽

Antioxidant Enzyme Activities ◽

Morphological Parameters ◽

Modern Cultivar ◽

Biochemical Responses

Crop production is unexpectedly hampered by different abiotic stresses. Salinity is one of the leading stresses, which snappishly hampers plant developmental progression. Local rice landraces exhibit noticeable salt tolerance as well as high yield. However, research is scarce about the physio-biochemical responses of local landraces and modern cultivar under saline conditions. Therefore, the present experiment was designed to reveal the physio-biochemical responses of local landraces and modern cultivar under salinity stress. Five landraces (Jotai, Icheburogolghor, Morishal, Chapail, Kumro buro) and two modern cultivars (BR23 and BRRI dhan41) were subjected to 0, 20, 40, 60 and 80 mM NaCl treatment. The effects of salt stress on morphological parameters, proline contents, and activities of antioxidant enzymes were assessed. Salt stress reduces the morphological parameters of all tested cultivars. The Morishal and BRRI dhan41 exhibited higher growth of plant and physiological parameters than other cultivars under the highest salinity. The catalase (CAT) and ascorbate peroxidase (APX), exhibited a significant increase whereas peroxidase (POX) activity significantly declined in all the cultivars under salinity stress. Morishal and BRRI dhan41 showed the highest proline content under the maximum saline condition. These results suggest that the high tolerant landrace and modern cultivars were Morishal and BRRI dhan41 respectively. These results also suggest that Morishal and BRRI dhan41 exhibited high tolerance to salinity by enhancing proline content and antioxidant enzyme activities.

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Polyamine Content Changes in Creeping Bentgrass Exposed to Salt Stress

Journal of the American Society for Horticultural Science ◽

10.21273/jashs03835-16 ◽

2016 ◽

Vol 141 (5) ◽

pp. 498-506 ◽

Cited By ~ 1

Author(s):

Yingmei Ma ◽

Emily Merewitz

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Canopy Temperature ◽

Leaf Tissue ◽

Creeping Bentgrass ◽

Extraction Process ◽

Canopy Temperature Depression ◽

Polyamine Content ◽

Chamber Studies ◽

Growth Chamber Studies

Salt stress is a major problem in turfgrass management. Investigation of metabolites, such as polyamines (PAs) that may improve salt tolerance of turfgrass species, is needed. Two independent growth chamber studies were conducted to evaluate physiological characteristics and changes in PAs, such as putrescine (Put), spermidine (Spd), and spermine (Spm), in response to salt stress in ‘Penncross’ and ‘PsgSLTZ’ creeping bentgrass (Agrostis stolonifera). The study also aimed to determine a method of PA extraction to improve PA yields from creeping bentgrass. Salt solutions were drench applied to plants growing in pure sand daily in a stepwise manner for ≈70 days in both studies. For both cultivars, salt stress caused an increase in leaf Na+ content, percent of electrolyte leakage (EL), and canopy temperature depression (CTD) while it caused a decrease in turf quality (TQ), osmotic potential (Ψs), and K+ and Ca2+ content compared with controls. In the early stages of salt stress, Put content increased in salt-stressed plants compared with controls. Spd content did not change significantly while a transient increase in Spm was observed in the later stage of salt stress. The PA quantification method used in this study included using formic acid during the extraction process, which exhibited enhanced quantification of PAs from creeping bentgrass compared with other methods previously published. Salinity stress upregulated the content of Put and Spm in leaf tissue, which may be involved in salinity tolerance in creeping bentgrass, while Spd accumulation may not be a major salt tolerance mechanism; supplementation with these biochemical compounds could be an alternative to improve creeping bentgrass salt tolerance.

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Chitosan regulates metabolic balance, polyamine accumulation, and Na+ transport contributing to salt tolerance in creeping bentgrass

BMC Plant Biology ◽

10.1186/s12870-020-02720-w ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Wan Geng ◽

Zhou Li ◽

Muhammad Jawad Hassan ◽

Yan Peng

Keyword(s):

Amino Acids ◽

Salt Stress ◽

Salt Tolerance ◽

Antioxidant Enzyme ◽

Osmotic Adjustment ◽

Photochemical Efficiency ◽

Creeping Bentgrass ◽

Antioxidant Enzyme Activities ◽

Metabolic Balance ◽

Gaba Accumulation

Abstract Background Chitosan (CTS), a natural polysaccharide, exhibits multiple functions of stress adaptation regulation in plants. However, effects and mechanism of CTS on alleviating salt stress damage are still not fully understood. Objectives of this study were to investigate the function of CTS on improving salt tolerance associated with metabolic balance, polyamine (PAs) accumulation, and Na+ transport in creeping bentgrass (Agrostis stolonifera). Results CTS pretreatment significantly alleviated declines in relative water content, photosynthesis, photochemical efficiency, and water use efficiency in leaves under salt stress. Exogenous CTS increased endogenous PAs accumulation, antioxidant enzyme (SOD, POD, and CAT) activities, and sucrose accumulation and metabolism through the activation of sucrose synthase and pyruvate kinase activities, and inhibition of invertase activity. The CTS also improved total amino acids, glutamic acid, and γ-aminobutyric acid (GABA) accumulation. In addition, CTS-pretreated plants exhibited significantly higher Na+ content in roots and lower Na+ accumulation in leaves then untreated plants in response to salt stress. However, CTS had no significant effects on K+/Na+ ratio. Importantly, CTS enhanced salt overly sensitive (SOS) pathways and also up-regulated the expression of AsHKT1 and genes (AsNHX4, AsNHX5, and AsNHX6) encoding Na+/H+ exchangers under salt stress. Conclusions The application of CTS increased antioxidant enzyme activities, thereby reducing oxidative damage to roots and leaves. CTS-induced increases in sucrose and GABA accumulation and metabolism played important roles in osmotic adjustment and energy metabolism during salt stress. The CTS also enhanced SOS pathway associated with Na+ excretion from cytosol into rhizosphere, increased AsHKT1 expression inhibiting Na+ transport to the photosynthetic tissues, and also up-regulated the expression of AsNHX4, AsNHX5, and AsNHX6 promoting the capacity of Na+ compartmentalization in roots and leaves under salt stress. In addition, CTS-induced PAs accumulation could be an important regulatory mechanism contributing to enhanced salt tolerance. These findings reveal new functions of CTS on regulating Na+ transport, enhancing sugars and amino acids metabolism for osmotic adjustment and energy supply, and increasing PAs accumulation when creeping bentgrass responds to salt stress.

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Halotolerant bacteria mitigate the effects of salinity stress on soybean growth by regulating secondary metabolites and molecular responses

BMC Plant Biology ◽

10.1186/s12870-021-02937-3 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Muhammad Aaqil Khan ◽

Atlaw Anbelu Sahile ◽

Rahmatullah Jan ◽

Sajjad Asaf ◽

Muhammad Hamayun ◽

...

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Plant Growth ◽

Salinity Stress ◽

Negative Impact ◽

Dry Weight ◽

Crop Productivity ◽

Stress Inoculation ◽

Bacterial Isolates ◽

Pgp Traits

Abstract Background Salinity is a major threat to the agriculture industry due to the negative impact of salinity stress on crop productivity. In the present study, we isolated rhizobacteria and evaluated their capacities to promote crop growth under salt stress conditions. Results We isolated rhizospheric bacteria from sand dune flora of Pohang beach, Korea, and screened them for plant growth-promoting (PGP) traits. Among 55 bacterial isolates, 14 produced indole-3-acetic acid (IAA), 10 produced siderophores, and 12 produced extracellular polymeric and phosphate solubilization. Based on these PGP traits, we selected 11 isolates to assess for salinity tolerance. Among them, ALT29 and ALT43 showed the highest tolerance to salinity stress. Next, we tested the culture filtrate of isolates ALT29 and ALT43 for IAA and organic acids to confirm the presence of these PGP products. To investigate the effects of ALT29 and ALT43 on salt tolerance in soybean, we grew seedlings in 0 mM, 80 mM, 160 mM, and 240 mM NaCl treatments, inoculating half with the bacterial isolates. Inoculation with ALT29 and ALT43 significantly increased shoot length (13%), root length (21%), shoot fresh and dry weight (44 and 35%), root fresh and dry weight (9%), chlorophyll content (16–24%), Chl a (8–43%), Chl b (13–46%), and carotenoid (14–39%) content of soybean grown under salt stress. Inoculation with ALT29 and ALT43 also significantly decreased endogenous ABA levels (0.77-fold) and increased endogenous SA contents (6–16%), increased total protein (10–20%) and glutathione contents, and reduced lipid peroxidation (0.8–5-fold), superoxide anion (21–68%), peroxidase (12.14–17.97%), and polyphenol oxidase (11.76–27.06%) contents in soybean under salinity stress. In addition, soybean treated with ALT29 and ALT43 exhibited higher K+ uptake (9.34–67.03%) and reduced Na+ content (2–4.5-fold). Genes involved in salt tolerance, GmFLD19 and GmNARK, were upregulated under NaCl stress; however, significant decreases in GmFLD19 (3–12-fold) and GmNARK (1.8–3.7-fold) expression were observed in bacterial inoculated plants. Conclusion In conclusion, bacterial isolates ALT29 and ALT43 can mitigate salinity stress and increase plant growth, providing an eco-friendly approach for addressing saline conditions in agricultural production systems.

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Salt tolerance of Glycyrrhiza inflata seedlings in Xinjiang and its ion response to salt stress

Chinese Journal of Plant Ecology ◽

10.3724/sp.j.1258.2013.00088 ◽

2014 ◽

Vol 37 (9) ◽

pp. 839-850 ◽

Cited By ~ 3

Author(s):

Jia-Hui LU ◽

Xin LÜ ◽

Yong-Chao LIANG ◽

Hai-Rong LIN

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Glycyrrhiza Inflata

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Genetic Potential for Salt Tolerance During Germination in Lycopersicon Species

HortScience ◽

10.21273/hortsci.32.2.296 ◽

1997 ◽

Vol 32 (2) ◽

pp. 296-300 ◽

Cited By ~ 46

Author(s):

M.R. Foolad ◽

G.Y. Lin

Keyword(s):

Salt Stress ◽

Salt Tolerance ◽

Genotypic Variation ◽

Control Treatment ◽

Molar Ratio ◽

Wild Accession ◽

Salt Tolerant ◽

Plant Introductions ◽

Genetic Potential ◽

Stress Levels

Seed of 42 wild accessions (Plant Introductions) of Lycopersicon pimpinellifolium Jusl., 11 cultigens (cultivated accessions) of L. esculentum Mill., and three control genotypes [LA716 (a salt-tolerant wild accession of L. pennellii Corr.), PI 174263 (a salt-tolerant cultigen), and UCT5 (a salt-sensitive breeding line)] were evaluated for germination in either 0 mm (control) or 100 mm synthetic sea salt (SSS, Na+/Ca2+ molar ratio equal to 5). Germination time increased in response to salt-stress in all genotypes, however, genotypic variation was observed. One accession of L. pimpinellifolium, LA1578, germinated as rapidly as LA716, and both germinated more rapidly than any other genotype under salt-stress. Ten accessions of L. pimpinellifolium germinated more rapidly than PI 174263 and 35 accessions germinated more rapidly than UCT5 under salt-stress. The results indicate a strong genetic potential for salt tolerance during germination within L. pimpinellifolium. Across genotypes, germination under salt-stress was positively correlated (r = 0.62, P < 0.01) with germination in the control treatment. The stability of germination response at diverse salt-stress levels was determined by evaluating germination of a subset of wild, cultivated accessions and the three control genotypes at 75, 150, and 200 mm SSS. Seeds that germinated rapidly at 75 mm also germinated rapidly at 150 mm salt. A strong correlation (r = 0.90, P < 0.01) existed between the speed of germination at these two salt-stress levels. At 200 mm salt, most accessions (76%) did not reach 50% germination by 38 days, demonstrating limited genetic potential within Lycopersicon for salt tolerance during germination at this high salinity.

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Characterization of Interactions between the Soybean Salt-Stress Responsive Membrane-Intrinsic Proteins GmPIP1 and GmPIP2

Agronomy ◽

10.3390/agronomy11071312 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1312

Author(s):

Jia Liu ◽

Weicong Qi ◽

Haiying Lu ◽

Hongbo Shao ◽

Dayong Zhang

Keyword(s):

Plasma Membrane ◽

Salt Stress ◽

Salt Tolerance ◽

Expression Profiles ◽

Expression Patterns ◽

Gene Expression Profiles ◽

Early Gene ◽

Plant Responses ◽

Constitutive Overexpression ◽

Important Trait

Salt tolerance is an important trait in soybean cultivation and breeding. Plant responses to salt stress include physiological and biochemical changes that affect the movement of water across the plasma membrane. Plasma membrane intrinsic proteins (PIPs) localize to the plasma membrane and regulate the water and solutes flow. In this study, quantitative real-time PCR and yeast two-hybridization were engaged to analyze the early gene expression profiles and interactions of a set of soybean PIPs (GmPIPs) in response to salt stress. A total of 20 GmPIPs-encoding genes had varied expression profiles after salt stress. Among them, 13 genes exhibited a downregulated expression pattern, including GmPIP1;6, the constitutive overexpression of which could improve soybean salt tolerance, and its close homologs GmPIP1;7 and 1;5. Three genes showed upregulated patterns, including the GmPIP1;6 close homolog GmPIP1;4, when four genes with earlier increased and then decreased expression patterns. GmPIP1;5 and GmPIP1;6 could both physically interact strongly with GmPIP2;2, GmPIP2;4, GmPIP2;6, GmPIP2;8, GmPIP2;9, GmPIP2;11, and GmPIP2;13. Definite interactions between GmPIP1;6 and GmPIP1;7 were detected and GmPIP2;9 performed homo-interaction. The interactions of GmPIP1;5 with GmPIP2;11 and 2;13, GmPIP1;6 with GmPIP2;9, 2;11 and GmPIP2;13, and GmPIP2;9 with itself were strengthened upon salt stress rather than osmotic stress. Taken together, we inferred that GmPIP1 type and GmPIP2 type could associate with each other to synergistically function in the plant cell; a salt-stress environment could promote part of their interactions. This result provided new clues to further understand the soybean PIP–isoform interactions, which lead to potentially functional homo- and heterotetramers for salt tolerance.

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